Synthetic resin and method of producing



Patented Jan. 5, 1937 UNITED STATES SYNTHETIC RESIN AND METHOD OFPRODUCING Irvin W. Humphrey, Wilmington, Del., assignor to HerculesPowder Company, Wilmington, Del., a corporation of Delaware No Drawing.Application January 29, 1935,

Serial No. 3,944

14 Claim.

This invention relates to a new composition of matter and method ofproducing and more particularly relates to a new class of resinousesters produced in accordance with this invention by the esterificationof acidic resins formed from certain terpenes and maleic anhydride.

The esters embodying this invention are in general slightly yellow incolor and may vary from viscous liquids to hard resinous solids,depending on the alcohol employed. They have desirable characteristicssuch as light resistance and durability to a high degree and areadaptable for various uses. Thus, for example, the esters embodying thisinvention will be found to be soluble in various solvents, to be ofdesirable color, and to resist discoloration and weathering. Further,for example, the esters lend themselves to use as plasticizers or resinsin nitrocellulose lacquers, the liquid esters in general having adistinct solvent power on nitrocellulose.

The resinous esters embodying this invention may be produced by theesterification of an acidic resin formed by the reaction of a plnene, asalpha-plnene, beta-plnene, etc., and maleic anhydride, or equivalentlymaleic acid, in the presence of heat, for example, as disclosed in myapplication for United States patent, Serial No. 688,360,- filedSeptember 6, 1933 now Patent 1,993,034.

The acidic resins may be prepared, as is more fully disclosed in theapplication above referred to, by heating a plnene, as alphaorbeta-pinene, with maleic anhydride. The reaction may be eftected in anysuitable manner, but will prefer- 5 ably be carried out by refluxing theplnene with the maleic anhydride. It is desirable to use an excess ofplnene, which can be recovered unchanged by distillation upon completionof the reaction. 1

The esters may be acid or neutral and may be prepared, and theirpreparation is contemplated, by various processes, as under atmosphericor other pressure, with and without the use of an esterificationcatalyst, etc., etc. Further, the esters may be prepared with the use01' various monohydric or polyhydric alcohols, aliphatic monohydricalcohols such as methyl, ethyl, butyl, n-propyl, isopropyl, bornyl,isobutyl, ,amyl, fenchyl, abietyl. etc. alcohols, substituted aliphaticalcohols, such as benzyl alcohol, ethylene chlorohydrin, etc. etc.,polyhydric alcohols, such as ethylene glycol, propylene glycol,glycerol, pentaerythrlte, etc., etc..and substituted polyhydric 55alcohols such as; glycerol monochlorohydrin,

glyceryl monoethyl ether, glyceryl monophenyl ether, etc., etc., are allcontemplated within this invention. Mixtures of various alcohols may beused if desired.

If desired, in the production of the ester, an 5 esterification catalystmay be employed and as such may be used, for example, sulphuric acid,.dry hydrogen chloride, metallic zinc or tin, paratoluene sulphonicacid, etc., etc. and the esterification may be eifected underatmospheric or 10 other pressure. Where low-boiling alcohols are used,superatmospheric pressure is especially desirable.

As illustrative of the practical production of esters in accordance withthis invention, using a 15 monoliydric alcohol, for example, the esterdiethyl-alpha-pinene-maleate may be prepared by mixing say one mole, say234 g, oil alphapinene-maleic anhydride with an excess of say ethylalcohol, say 368 g. and adding as an esterification catalyst about 8% byweight or about 50 g. of concentrated sulphuric acid. The mixture, of alight yellow color, is then kept at a gentle reflux, for say about'48hours by, for example, heating at a temperature of about 100 0. 25

On completion of the heating period the re-. sultant liquid is washedwith water to remove the excess alcohol and sulphuric acid and thengiven an alkali wash, say with sodium-carbonate solution, to remove anytraces or sulphuric acid and any acid ester present. The product is thengiven a final water wash and the ester, which is a viscous liquid, isthen dried say .with anhydrous potassium carbonate.

Kit is desired to further purify the ester, it may be distilled underreduced pressure, a part distilling at 195 C.--210-C. under a pressureof 15 mm. mercury. The residue which does not distill consists of theester of the polymerized anhydride. Alternatively the ester may berefined by heating to a temperature of about 150 C. and passing in airor some inert gas.

As further illustrating the production of the ester embodying thisinvention, for example, for the preparation of the esterdibutyl-alphapinene-maleate, say 234 g. oi. alpha-pinene-maleicanhydride and 296 g. of butyl alcohol are mixed together, that is 4 molsof butyl alcohol for each mol. of anhydride, and then heated for say '7hours at a temperature of say ll'lf C., the boiling point of butylalcohol. The reaction will result in the formation of .mono-butylalpha-plnenemaleate, which will be found to be av pale yellow,

soft solid, which will remaindissolved in the excess alcohol. About 8%by weight of concentrated sulphuric acid is then added and the mixtureis heated for approximately 40 hours at the same temperature, about 117C. The result of the reaction will be the formation ofdibutylalpha-pinene-maleate.

On completion of the heating period the reaction mixture is washed withwater to remove the sulphuric acid. The excess butyl alcohol is thenremoved by distillation. If desired, the ester may be distilled underreduced pressure for its purification or may be purified by air blowingat a temperature of approximately 150 C. It will be noted that volatiledibutyl alpha-pinenemaleate distills at about 210 C.-230 C. under apressure of 15 mm. mercury. The ester will be found to be slightlyyellow in color and rather viscous. The residue remaining after thedistillation of the volatile ester consists of the ester of thepolymerized anhydride As illustrative of the practical adaptation ofthis invention, when a polyhydric alcohol for the esterification isemployed a simple ester does not result. Polymerization takes place andthe type of product formed is directly dependent on the alcohol employedas well as the temperature at which combination is allowed to takeplace. Thus, for example, when a dihydric alcohol is used, such asethylene glycol, a hard resinous solid which is soluble in lacquersolvents results. When a polyhydric alcohol having more than twohydroxyl groups is used, on the other hand, the esterification ifcarried sufficiently far will lead to the formation of an insoluble gel.To avoid gelation it is necessary to employ an excess of the polyhydricalcohol or to interrupt the reaction just as gelation is about to com-vmence.

As illustrative of the practical adaptation of this invention with useof, for example, a dihydric alcohol, the esterification may be carriedout with, for example, ethylene glycol as follows: Thus, for example,270 parts by weight of alpha-pinene-maleic anhydride and parts ofethylene glycol are heated together with good agitation at a temperatureof 205 C.-2l5 C. for approximately 8 hours. Excess glycol may be removedby applying reduced pressure. As a result of this treatment a hard, paleyellow, resinous solid is formed. It will be found to have an acidnumber of about 45 and a drop melting point of C. to C. It is soluble inorganic solvents such as acetone, toluol, butyl acetate, etc., but isinsoluble in alcohols.

Further, when a polyhydric alcohol such as glycerol, having threehydroxyl groups, is employed in the esterification, the esterificationmay be carried out in the following manner: Thus, for example, 300 partsby weight of alpha-pinchemaleic anhydride and 100 parts by weight ofglycerol are heated together with agitation at a temperature of C.-200C. for 8 to 10 hours. After this heating the product is a pale yellow,hard and brittle resin having an acid number of about '75 and a dropmelting point of 95 C. to 100 C. By continuing the heating, preferablyin a thin layer, an insoluble and infusible product may be produced.Such a product is useful as a molding material.

The following example illustrates the method of carrying out theesterification with a substituted polyhydric alcohol, for example, onehaving the hydrogen of at least one hydroxyl group replaced by an alkylor aryl radical to form an ether. Thus, for example, 23 parts by weightof alpha-pinene-maleic anhydride and 13 parts of glycerol monoethylether are heated together at a temperature of 220 C.-230 C. forapproximately 20 hours. The resulting product is a light yellow, softresin, soluble in lacquer solvents and having an acid number of about 60and a drop melting point of 60 C.

In place of alpha-pinene-maleic anhydride, beta-pinene-maleic anhydridemay be used in the examples given above in equivalent amount.

The use of mixtures of more than one alcohol for the esterification isalso contemplated. Thus, for example, a monohydric alcohol such as butylalcohol and a polyhydric alcohol such as glycerol may be used incombination to give mixed esters. The combination in such a case may becarried out in any manner such as partial esterification first withbutyl alcohol then completion of the esterification with glycerol, orvice versa.

It will be understood that the esters in accordance with this inventionmay be prepared by various methods other than those specificallyoutlined above. For example, the production of the esters may beeffected at temperatures within the range of about 75 C. to 250 C. andthe pressure may vary from atmospheric to about 300 pounds per squareinch. The period required for esterification will, of course, dependupon the temperature and pressure employed.

It will be understood that in accordance with this invention substitutedmonohydric and substituted polyhydric alcohols are contemplated asincluded as equivalents within the terms "monohydric and polyhydric"alcohols as used in the claims appended hereto.

It will be understood that the esters in accordance with this inventionwill be found to possess various desirable characteristics and to beadaptable for various uses, such, for example, as an ingredient inlacquers, varnishes, and the like, together with the various well knowningredients thereof, as solvents, nitrocellulose, drying oils,plasticizers, gums, resins, etc., etc. and will be found especiallyadaptable for use as a plasticizer in connection with nitrocelluloselacquers in view of its excellent plasticizing properties and itsproperties as a solvent for nitrocellulose.

It will be understood that the resinous esters from polyhydric alcoholsin accordance with this invention may be modified during theirproduction by the inclusion in the reaction mixture of various modifyingagents, such as, rosin and other natural resins; animal or vegetableoils, especially the drying oils, for example, linseed ofl, Chinawoodoil, etc.; organic acids, for example, oleic acid, linoleic acid,stearic acid, succinic acid, or its homologues, acids derived fromChina-wood oil,- etc. Such modified resins are especially adaptable foruse in lacquers, varnishes, plastics, etc.

I have not specifically claimed herein my invention as it relates tomodified resins and their production, since such are the subject matterof and are claimed in my copending application, Serial No. 3,943, filedJan. 29, 1935.

This application is a continuation in part of the application filed byme, September 6, 1933, Serial No. 688,360.

What I claim and desire to protect by Letters Patent is:

1. A reaction product of a pinene-maleic anhydride and an alcohol.

2. A reaction product of a pinene-maleic anhydrlde and an aliphaticalcohol.

. 2,087,654 3 3. A reaction product of a pinene-maleic anhy-, 11. Themethod of producing a resinous madried and apolyhydric alcohol. terialwhich includes reacting alpha-pinche- 4. A reaction product of apinene-malelc anhymaleic anhydride with an alcohol. dried and amonohydric alcohol. 12. The method oiproducing a resinous ma- 5 5. Areaction product 01' a pinene-maleic anhyterial which includes reactingbeta-pinene-maleic 5 dride and ethyl alcohol. anhydride with an alcohol.

6. A reaction product of a pinene-maleic anhy- 13. A coating compositioncomprising a reacdride and glycerol. tion product of an alcohol and apinene-maleic- 7. A reaction product of a pinene-maleic anhyanhydride,and a solvent.

10 dride and an aliphatic glycol. 14. A coating composition comprising areac- 1o 8. The method of producting a resinous mation product of analcohol and a plnene-maleic terial which includes reacting apinene-maleic anhydride, a non-volatile lacquer ingredient and anhydridewith an alcohol. a solvent.

9. A reaction product of alpha-pinene-maleic 15 anhydride and analcohol. IRWIN W. HUMPmEY. 15

10. A reaction product of beta-pinene-meleic anhydride and an alcohol.

